Ischemic damage is understood as pathosis including any and all symptoms caused by a restricted blood flow at any part of the body, wherein cells are necrotized by energy depletion in an ischemic region, so that the region falls into dysfunction. As a method of treatment for a case that the ischemia is caused by a thrombus, the development of a thrombolytic drug and a thrombolytic drug therapy using the same has been pursued with an object of lysing the thrombus to recover the blood supply to the ischemic region.
For example, a thrombolytic drug of alteplase (recombinant DNA tissue plasminogen activator, rt-PA) has been developed focusing attention on the action of the plasminogen activator (t-PA). According to Brain Res., 2000; 854: 245-248, alteplase activates plasminogen to plasmin, and the plasmin degrades fibrin, which constitutes a nucleus to generate a thrombus.
Further, SMTP (Stachybotrys microspora triprenyl phenol) compounds are a group of compounds having a triprenyl phenol skeleton produced by a filamentous bacterium, and are known to have a thrombolysis promotion action or a vascularization inhibitory action according to Japanese Patent Laid-Open No. 2004-224737, Japanese Patent Laid-Open No. 2004-224738, and WO2007/111203. With respect to the thrombolysis promotion action, an action mechanism is indicated by FEBS Letter, 1997; 418: 58-62, that an SMTP compound causes a change in the conformation of plasminogen resulting in increasing the sensitivity of the plasminogen to t-PA and the binding of the plasminogen onto a thrombus etc. so as to promote lysis of the thrombus.